METASTATIC SMALL-CELL CARCINOMA OF THE PROSTATE DIAGNOSED BY FINE-NEEDLE ASPIRATION BIOPSY

Fourteen fine-needle aspiration biopsies (FNABs) of metastatic small-c ell carcinoma done on 12 patients who had histologically documented pr imary small-cell carcinoma of the prostate are described. The FNABs we re of lymph node (four cases), liver (four cases), bone (two cases), p ancreas (one case), perirectal soft tissue (one case), perineum (one c ase), and lung (one case). One patient underwent three FNABs. No patie nt has a second primary tumor elsewhere. Cytologic smears were cellula r with numerous single tumor cells, many apoptotic bodies, and variabl e numbers of mitotic figures. Tight cell clusters with molded nuclei a nd finely stippled chromatin were seen in all cases. An organoid patte rn of tumor cells was seen focally in two cases. Features distinguishi ng small-cell carcinoma from poorly differentiated prostate carcinoma were cell size, finely stippled chromatin, inconspicuous nuleoli, and numerous single tumor cells. Distinction from small-cell carcinoma of other primary sites requires clinical and radiologic correlation. We c onclude that cytologic specimens are useful for documenting metastatic small-cell carcinoma of the prostate and for differentiating between it and conventional prostate carcinoma in metastatic sites. (C) 1998 W iley-Liss, Inc.